Referring to FIG. 1, a microstrip reflectarray 10 is a low profile reflector, consisting of an array of microstrip patch antenna elements 20 disposed on a surface 15 capable of reflecting energy to or from feed 25. Reflectarrays are flat, inexpensive, easy to install and easy to manufacture. By loading each microstrip patch antenna element 20 with a single varactor diode 30, as depicted in FIG. 2, a progressive phase distribution can be achieved in the microstrip reflectarray 10, see the paper by Luigi Boccia, et al., entitled “Experimental Investigation of a Varactor Loaded Reflectarray Antenna,” 2002 IEEE MTT-S Digest, pages 69-71. Although the microstrip reflectarray 10 containing microstrip patch antenna elements 20 with varactor diodes 30 allows beam steering, the microstrip reflectarray 10 operates at a single frequency band and in a single polarization.
Unlike prior art, it is possible to operate a reflectarray according to the present disclosure at dual frequencies and it is possible to operate a reflectarray according to the present disclosure at dual frequencies and in dual polarization.